The Glass Wall
by lumixedia
Summary: An attempt to bring Mycroft and Eurus's relationship to a satisfying resolution after she locks him up in her old cell during The Final Problem. Features anger, despair, love, catharsis, and a happy ending.


Cold.

Hard floor.

Strange tingle in the neck.

Harsh light.

 _Sherlock pointing that gun at his chin and counting down from ten. Eurus shouting "Stop that at once!" Dizziness, then nothing, then-glass wall, violin case in the corner, this is her cell. Nobody else here. Tranquilizer dart. She must have hit him too, she must have stopped him too, she said she would and she still wants to play with him, there's no way she could possibly have allowed him to die, either accidentally or deliberately. Is there?_

Mycroft slowly maneuvered himself into a sitting position, then a standing one.

Obvious stupid thing to try, number zero: check the locks on the cell doors. They were, in fact, locked. One of the locks had had a vulnerability once, but he himself had found and fixed it.

Obvious stupid thing to try, number one: scream.

"SHERLOCK!" Mycroft howled. Pause. No response. "DOCTOR WATSON!" Pause. No response. "ANYONE!" Pause. No response. "HELP!" Pause. No response.

 _I was supposed to die while Sherlock and Dr. Watson moved on to the next phase of the game. I am not dead, but presumably everything else is proceeding as planned. But what could her plans be? Whatever they are, I'm not part of them. There's nothing I can do._

The moment he thought _there's nothing I can do_ , the video screen on the wall turned on.

"Good morning, Mycroft, you're up early!" Eurus sang. "Aren't you supposed to be dead?"

Mycroft spun around. The video feed was shaky and filled with background noise; Eurus appeared to be calling from a helicopter. "Where are Sherlock and Dr. Watson and what are you going to do with them?" That was obvious stupid thing to try, number two: ask.

"They're not at Sherrinford anymore," Eurus said, smiling. "It's back to the mainland with them. You're all alone here."

"Where are you taking them?" Mycroft persisted.

"Why does it matter?" Eurus laughed. "Your job is to sit here and wait out the rest of the game. There's nothing you can do."

"If there's nothing I can do, why don't you just tell me?"

"Oh, you're right," Eurus said. "That's how the stories go, isn't it? I'm supposed to tell you all about the horrors you can no longer stop, to torment you. But I don't think that's necessary. I trust your imagination will do a fine job of that all by itself." She cut the connection.

 _Alive, but not at Sherrinford. Back to the mainland. Where? What is this all about? Sherlock. This is all about Sherlock, and the childhood they almost had together. They must be going to Musgrave. For what?_

 _Sherlock and Dr. Watson. Sherlock and Victor Trevor. Help succor me now the East Winds blow, sixteen by six and under we go. That damned well. How can it be that we went over every inch of the property with the police and never found that damned well? But of course nothing gets found if Eurus doesn't want it found, especially if she's allowed to talk to the people who are looking. I wonder if anything would be different now if I had found the well. I wonder if that would have fixed anything._

Mycroft paced back and forth through the cell, waiting.

"Hello again, Mycroft!" The video screen turned back on. The helicopter had landed, and Eurus was exiting. "The boys are still asleep. I'm bored. Are you bored yet?"

He took a deep breath. As long as she kept talking to him, he had a chance. He just had to try a different tactic. "Eurus, I'll play with you. Why not play with me? Sherlock is so slow, anyway. He'll never be clever enough for you. You might as well leave him alone."

"Oh?" Eurus said, clearly unimpressed. "And what would you like to play?"

"Anything you want."

She shook her head, sighing. "But I don't want to play with you, Mycroft. You're not like Sherlock. You're no fun."

"Why not?"

She sighed again, dramatically. "You just _aren't_. You're too afraid. Always thinking about safety, never about life. You know when you're fun? When you're locked up and helpless and you want to _interfere_ like you always do but there's absolutely nothing you can do. Then"-a small giggle-" _then_ , at least, you're entertaining. Your nails are going to cut your palms if you keep clenching your hands like that."

Mycroft belatedly noticed the pain in his hands and forced them to relax, grimacing. "Can I at least convince you that you'll have more-fun-in the long run if you don't do them irreparable damage?"

Eurus rolled her eyes. "Oh, what do you care? Sherlock was about to _kill_ you for John Watson." She mimed a gun at the camera with her free hand and jerked it up. "Bang."

"What does that have to do with anything?"

"Maybe it means you should worry about yourself instead of them. Just for a few minutes. I could leave you there for _weeks_ , you know. I could leave you there _forever_." And with that, she cut the connection again.

Mycroft rubbed his temples. There were so few things in the world that he couldn't figure out. Why, just why, did one of them have to be his only sister?

 _Where did I go wrong? What should I have done better? Should I have paid more attention to her? I tried, but she always pushed me away. Should I have told Sherlock to pay more attention to her? Impossible, she scared him so much. Should I have been stricter? Should I have found the well earlier?_

He continued pacing the cell, tapping his fingers against the glass wall, re-examining all the locks. According to Sherlock, it was Eurus who'd gone to all the trouble of having the cell remodeled so that the wall could be slid aside, then installing new locks on the sliding mechanism so that it would still keep Mycroft in. All, apparently, to make some kind of convoluted point he didn't understand.

 _Should I have risked letting her see Mum and Dad, after what she almost did to them? Impossible. Should I have transferred her away from Sherrinford, when it turns out even Sherrinford can't hold her? Impossible. Should I have denied her Moriarty, given the alternatives we were facing at the time? Impossible, impossible, impossible!_

He contemplated the glass with unspeakable frustration.

"Are you sick of it yet, Mycroft?" The screen flicked on once again. "Are you sick of being lost in the middle of the ocean?"

Mycroft stared at the background of the video, at the section of wall in a long-abandoned yet still-familiar room. Eurus was at Musgrave. And her mood had changed. She looked-was it possible?-anxious. Frightened, even. It was true, she had not been happy at Musgrave all those years ago-none of them had been, once she started slipping away. Still, what could Eurus Holmes, of all people, possibly be afraid of?

"This is it, Mycroft," she said, her brows pinched with nervousness. "It's all up to Sherlock now. If he fails, John Watson will drown, and the little girl will fly through the sky forever and never find land."

Forever. Forever? Mycroft blinked. "You mean-you. _You're_ the girl in the plane."

"Yes!" Eurus shouted, angrily, as if he should have gotten it earlier. "I'm the girl in the plane, and all you've ever done for me is try to crash me into the ocean, away from other people who might get hurt! Well, it didn't work! People got hurt anyway! So you, you can just go rot in the little box where you left me until you sink beneath the waves! What goes around comes around!"

"Eurus-Eurus-" Mycroft stared at the lines of distress on his sister's face, feeling his frustration curdle into a sharper, deeper pain. He had never seen her like this, and it hurt beyond imagining. "You gave me no alternatives! You must know how hard I looked for alternatives! You must know I would have locked myself here in your place if I thought it would help you! I tried-I tried"-he was becoming slightly hysterical-" _you know I tried!_ "

"I don't _care_ if you tried!" Eurus shrieked. "That's just your _problem_ -you always had to _try_! I don't care how many Stradivariuses you buy me or how often you come to my cell to pester me or how much time you spend arguing with the administrators about my _comfort_! You aren't the brother I want, you aren't the brother I need, and no amount of _trying_ will change that!" The screen went black.

"No, no, come back! Eurus, come back!" Mycroft cried. " _Please!_ "

No response.

He groaned and slid to a sitting position, leaning his side against the glass wall. It was no use shouting. She was right, anyway. Whatever it was she needed-whatever it was _they_ needed, both of them-he didn't have it. Jailer. Archenemy. Iceberg. Reptile. Whatever he was, he was no brother.

 _There's nothing I can do. There's nothing I've ever been able to do. Nothing. Nothing. Nothing. Nothing. Nothing. Nothing._

 _Nothing. Nothing. Nothing._

 _Nothing._

An indeterminate amount of time passed. He leaned back, wiped his face, and closed his eyes. "Sherlock, please," he whispered to the cold ocean air. "You were always the sunny one."

And the video screen turned on again.

Eurus was standing in the middle of a forest. There were unidentifiable people making hurried, urgent noises in the background, but she looked-better. Still anxious, still lost-but in the lines of anxiety there were traces of hope.

"He solved it," she said, softly, wonderingly. "He said he can help me."

Mycroft was instantly on his feet, his heart pounding. "Sherlock and Dr. Watson-"

"They're fine." She looked down, away from the camera. "I'm sorry."

"What?"

"I'm sorry for always being angry with you. It's not your fault we were born on opposite sides of a glass wall." She raised her eyes again. "Don't stop visiting me."

It was hard to speak, hard to think, with the jumble of emotion-relief, and worry, and the old, still-harsh pain-bouncing around in his mind. "As much as you want," he managed. "But you said you didn't care."

"I was lying," Eurus said, almost affectionately, and hung up for the final time.

* * *

 _Several weeks later._

"Write something for us next time," Sherlock said.

They were on the beach at Sherrinford, having slipped away from their parents in the dining hall. The wind whipped across the sand like it always did, and the waves crashed orchestrally against the rocks.

"What?"

"I'm not going to waste my time trying to convince you to play with us. I wish you would, but it's not your style. But I know you can compose."

"How-do-you-know-that?" Mycroft sputtered.

"Because I found the music room in your basement!" Sherlock giggled. Standing beside the sea, with the wind tossing his hair, he looked somehow more the part of a pirate than ever. "It was so well hidden, I thought you were keeping bodies in it. And I've never seen such good soundproofing."

"For a _reason_!" Mycroft groaned. He should never have invited Sherlock into his house. He should have made him sleep on the street until Baker Street was rebuilt. To let Sherlock break in on occasion was one thing. To let him have the run of the place for weeks was, evidently, quite another.

"I've already photographed your most promising drafts," Sherlock continued happily. "Eurus and I are going to expose your embarrassing little secret the next time we're here no matter what you do. But if you'd like us to play something a little more…polished, just say the word." He spread his arms wide, embracing the wind and the sky. "Join us, brother mine! Let the music out!"

Mycroft opened his mouth to object, but nothing came out. The problem was, it was hard to focus on arguing with Sherlock when the first few bars of a new piece were already playing in his head. They were sweet, and fierce, and full of joy that burned like pain and pain that sang like joy, and they sounded like a glass wall shattering.


End file.
